Pickup truck cargo beds are generally secured along the length of a vehicle frame with a support structure, which typically includes two generally parallel frame members interconnected and spaced apart by cross members to create what is commonly known as a ladder frame. However, such known support structures for cargo beds do not always match load distribution patterns of the vehicle, which may result in poor body stiffness. Further, conventional cargo beds may experience potential durability concerns such as cracking, corrosion, or other structural issues, which may be produced or magnified when the cargo bed support structures do not match the load distribution patterns. Accordingly, it is desirable to provide an improved cargo bed or vehicle underbody structure to more closely match the load distribution patterns of the vehicle.